6.1.2.2. A delayed coke complex is depicted in Figure 6.1.2.3.
The refinery residues are heated in a furnace (b) up to about 485–500 °C. After passing a fractionator tower where middle distillates are topped off, they are fed into one of the coking chambers. The energy gained in the furnace passages is sufficient to release the cracking reaction in the filling time of the coking chamber (delayed coking). The reaction zone is also called mesophase, because the transition from liquid residue molecules to solid crystalline coke structure occurs here. The pressure in the coking chamber can be varied between 2 bar and 6 bar. In the furnace, steam is dosed to the residue to inhibit the formation of coke. The vapors in the coking chamber – gases, naphtha, middle distillates, and heavy coker gas oil – are routed to the fractionator for separation, then fractionated, and forwarded for downstream units for posttreatment. The heavy coker gas oil is recycled as coker feed or is used in other refinery processes such as hydrocracker or gas oil hydrotreater or as feed to fluid catalytic cracking unit [11].
Table 6.1.2.1 Refineries with petroleum coke production 2005.
| Refinery | Estimated production Mta 2005 | Typical analysis % S | Current FOB price | US$ |
|---|---|---|---|---|
| North America | ||||
| East Coast | ||||
| Motiva, Delaware City | 0.70 | 5.6 | 34 | 15–18 |
| Valero Energy, Paulsboro | 0.50 | 5.0 | 100 | No export |
| West Coast | ||||
| Tesoro | 0.30 | 6.5–7.0 | 50 | 35– |
| BP, Cherry Point | 1.00 | 3.5 | 45 | Anode grade |
| Chevron, El Segundo | 1.10–1.20 | 4.0–4.5 | 65–70 | 49–51 |
| Bakersfield | 0.25 | 0.9 | 30 | |
| Shell, Martinez | 0.42–0.45 | 1.1–1.5 | 40 | 50–55 |
| Shell, Wilmington | 0.630 | 2.6 | 53–55 | 55– |
| ExxonMobil, Torrance | 1.10 | 1.1–1.5 | 50 | 60– |
| ConocoPhillips, Santa Mariaa) | 0.35 | 4.8 | 65 | — |
| ConocoPhillips, Carson | 2.6–3.0 | 40–42 | 48–50 | |
| ConocoPhillips, Rodeo | 0.40 | 0.9 | 85 | Anode grade |
| Tesoro Golden Eagle | 0.43 | 2.5 | 28 | 37–40 |
| Valero, Wilmington | 0.60 | 4.2–4.5 | 60–65 | 49–51 |
| Valero Benicia | 0.40 | 3.5 | 30–35 | 30– |
| US Gulf | ||||
| Marathon Galveston Bay refinery | 0.90 | 5.0–5.5 | 80 | 28–29 |
| Chevron, Pascagoula | 2.50 | 6.3 | 35 | 25–26 |
| CITGO, Corpus Christi | 0.90 | 3.9–4.1 | 46–47 | 29–30 |
| CITGO, Lake Charles | 1.40 | 3.7 | 60–65 | 29–30 |
| LyondellBasell | 2.00 | 4.0–4.3 | 45–48 | 29–30 |
| ConocoPhillips, Lake Charles | 1.30 | 6.0–6.2 | 40–42 | 26–27 |
| Valero, Corpus Christi | 0.40 | 5.8–6.2 | 77–80 | 25–26 |
| ExxonMobil, Baton Rouge | 1.30 | 4.5–5.0 | 50 | 28–29 |
| ExxonMobil, Chalmette | 0.65 | 4.5 | 55–60 | 29–30 |
| ExxonMobil, Beaumont | 1.10 | 5.8 | 65–67 | 27–28 |
| ExxonMobil, Baytown | 1.00 | 6.2–6.3 | 47–50 | |
